1. Field of the Invention
The invention relates to a vacuum gripping device, in particular a surface vacuum gripper.
2. Description of the Related Art
Vacuum gripping devices are usually equipped with a plurality of suction bodies disposed adjacent to one another at suction points of a working surface of a gripper housing. The suction bodies are each designed to apply a suction to a workpiece that is to be gripped. With vacuum gripping devices of this type, a suction valve is allocated to each suction element. A vacuum gripping device having features of this type is described in DE 690 08 874 T2.
Those suction valves, in particular, which close automatically when the suction point is unoccupied, and thus prevent an undesired leakage from the suction side of the valve to the vacuum supply side, are suited for this. A valve of this type is disclosed, for example, in DE 198 14 262 C2. This valve has a valve body, which is disposed on a flexible, wall-like section that delimits a control chamber of the valve. The control chamber is connected to the vacuum supply side. The pressure of the suction side of the valve bears on the other side of the wall-like section. The control chamber, however, is closed off from the suction side, in terms of flow, by the wall-like section. When the control chamber is compressed, the flexible section is deformed, such that the valve body is moved to its closed position. If a suction occurs in the unoccupied state of the suction side, then no appreciable vacuum is obtained at the suction side. As a result, the control chamber is compromised, due to the static pressure difference between the control chamber and the suction side, and thus the valve body is brought into its closed position. The valve thus closes automatically when the suction side is unoccupied. Such valves have a complex structure and must be adjusted to the properties of the suction device that is to be controlled pertaining to flow technology, in particular in order to adjust the response sensitivity of the automatic closing. The integration of such valves in a vacuum gripping device is thus associated with structural challenges.
Other types of vacuum gripping devices are described in U.S. Pat. Nos 8,070,156 B2, 5,374,021 A, FR 2 561 221 A1 and WO 83/04384 A1. These, however, do not have any suction bodies allocated to the suction points. Instead, these vacuum gripping devices have a flat terminal suction plate that is to be placed on the workpiece that is to be gripped.